1. Field of the Invention
The present invention generally relates to mixers for use in mixing plaster, mortar or the like and includes a pivotally mounted drum which can be pivoted to a dumping position about a horizontal axis together with a rotatable paddle assembly disposed interiorly of the drum and driven by a prime mover mounted on a portable frame or the like in which the paddle assembly includes a novel and unique stub shaft mounting for the paddle shaft and paddles and a drive system enabling alternate use of an electric motor or a small internal combustion engine either of which is readily available without necessitating the purchase and utilization of a relatively expensive reduction gear unit.
2. Description of the Prior Art
Plaster and mortar mixers which include a pivotal drum in which mixing paddles rotate have been manufactured by the assignee for a number of years with prior U.S. Pat. Nos. 3,334,871, issued Aug. 8, 1967 disclosing a cover guard arrangement for the mixing drum, 3,905,519, issued Sept. 16, 1975 illustrating a latching and unlatching assembly for the pivotal mixing drum. Other prior patents such as U.S. Pat. Nos. 1,630,789, issued May 31, 1927, 2,668,695, issued Feb. 9, 1954 and 1,708,947, issued April 1929 disclose mixers of this type. Such devices usually are mounted on a wheeled frame and a prime mover is mounted on the frame and is in driving connection with a paddle shaft which extends longitudinally through the mixer drum with a plurality of paddles being secured to the paddle shaft. A large gear is attached to the paddle shaft externally of the drum and is in meshing engagement with a smaller pinion gear which, in turn, is drivingly connected to an electric motor or a small internal combustion engine of appropriate horsepower. In view of the relatively slow rotational speed required for the paddle shaft, a reduction gear unit is usually obtained along with the prime mover as a composite unit which materially increases the cost of the mixer since conventional and universally employed electric motors or internal combustion engines cannot be used. In addition, the individual paddles are bolted to the paddle shaft which enables removal of the paddles but also introduce a bolted joint which sometimes can become loosened and requires each paddle to be individually removed from the paddle shaft in order to replace wear components provided on the paddles.